This invention relates to a motion base for an apparatus for subjecting a user to sensory experience. In particular, this invention relates to a motion base for use in virtual reality or other simulator-type theme park attractions.
"Virtual reality" is a phrase that has been used to describe the experience of living or playing in a computer simulated environment which models a three dimensional ("3-D") virtual space (i.e., a virtual world). In virtual reality systems, a viewer typically dons a set of goggle-mounted video screens or some other form of head-mounted device on which the viewer sees images of virtual world scenes. In addition, the user may be able to interact with objects in the virtual world by maneuvering a pointing device which is typically gripped by the hands. Through the pointing device, the user is thus able to actively influence and participate in events in the virtual world.
Virtual reality systems incorporating visual images and user input have been extensively used in military and commercial applications, such as flight simulators. Virtual reality systems may also be used in entertainment applications including computer games, video arcade games and theme park attractions.
In applications such as virtual reality theme park attractions, it is particularly important for the motion imparted to the apparatus of the attraction, and hence to the user, to correspond realistically to the user's input from the pointing device, thereby enhancing the user's sense of immersion in the virtual world.
Known motion bases for virtual reality and other simulator-type attractions generally include apparatus having some type of stationary platform from which the user enters the apparatus and as many moving parts as are necessary to carry out the type of motion suitable to the theme of the particular attraction.
The moving parts of such an apparatus can experience movement relative to each other and relative to the stationary platform. As a result, such attractions may pose safety concerns for their users. For example, the relative movements of the various component parts of the apparatus with respect to the stationary platform could leave enough open space for a hand or foot of a user, either on the stationary platform or the moving platform, to become caught therebetween.
Flexible coverings or skirts have sometimes been employed for the purpose of increasing the user safety of such attractions. Such coverings generally conceal the gap that would appear between, for example, the stationary platform and a moving part once that particular part began to move. However, such methods have not proved entirely successful. The coverings sometimes limit the degree of movement that the components of the apparatus can experience. They may not always be strong enough to prevent injury. In addition, they are subject to stress and fatigue and may fail without warning. Also, they may decrease the overall aesthetic appearance of the attraction for the user.
A further disadvantage of known simulator motion bases, particularly those used for military and commercial flight simulators, is that they generally employ apparatus in which the active elements that impart motion to the mechanism also bear the load of the user's weight. For example, in many aviation simulators, the entire simulator base is supported by the pistons that also impart the simulated motions. This is undesirable for several reasons. First, the active elements must exert sufficient force not only to move the platform and the user, but also to support their weight. This means that larger, more expensive active elements are required, and also that the lifespan of the active elements may be reduced. Second, a failure of the active elements while the apparatus is in motion could result in collapse of the platform and injury to the user.
Finally, in known motion bases, if rotational motion is imparted to the user, the center of rotation of the apparatus may not be coincident with the user's center of gravity. As a result, such an apparatus can cause nausea or other motion sickness for the user. In addition, if the user's center of gravity is not coincident with the center of rotation of the apparatus, higher torque is required to rotate the apparatus. In one known amusement attraction, the user is held within a sphere-like frame which is gimballed to a fixed support for rotation about multiple axes. Thus, the center of rotation of the apparatus is about the center of the sphere. In such an apparatus, if the center of rotation is not also about the user's center of gravity, the moment between the center of the sphere and the user's center of gravity would necessitate the application of higher torque to subject the user to motion. Likelihood of user nausea would also be increased, and the user's sense of immersion in the experience would be decreased by the unnatural motion.
Thus, it would be desirable to provide a motion base for an apparatus for subjecting a user to sensory experience that requires less force and torque to cause the base to move in a desired manner.
It would also be desirable to provide means for imparting motion to a motion base that contributes to prolonging the life of the apparatus.
It would also be desirable to provide a motion base that can be made from high strength materials at a reduced cost.
It would also be desirable to provide a motion base that can impart motion to a user in a manner that realistically corresponds to the user's input.
It would also be desirable to provide such a motion base that lessens the likelihood that the user will suffer nausea or other motion sickness, and that thereby increases the user's sense of immersion in a virtual world.
It would further be desirable to provide a motion base for an apparatus for subjecting a user to sensory experience that provides a high degree of safety for the user.